Vapor generator



June 1, 1943;

Filed May 13, 1939 5 Sheets-Sheet 1 n6 i j! 3 3 v l i I22 IO\ 46 3? v v34 I34 35 '32 :121

BY Era m G'fijzzley ATTORNEY.

June 1, 1943. E. G. BAILEY VAPOR GENERATOR Filed Kay 13, 1939 5Sheets-Sheet 2 llll] llllilllllllll-IHII E. G. BAILEY June 1, 1943.

vAPon GENERATOR Filed May 13, 1939 5 Sheets-Sheet 3 (I) I C D INVENTOR.

Erwin GBaile BY ATTORNEY.

June 1, 1943. E. e. BAILEY 2,320,343

' VAPOR GENERATOR Filed May 13, 19:59 v5 Sheets-Sheet 4 I HM, MM. Mmltl'I low nfit er Level I i l P131 1 1- INVENT OR.

Jun 1, 1943.

E. G. BAILEY VAPOR GENERATOR Filed May 13, 1939 5 Sheets-Sheet 5 H 19hMderlevel HEBQ Q QW Lazy Waterlevel m Drum;

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lilll BY Egin GBai/e buzz.

INVENTOR.

y W. W ATTORNEY.

Patented June 1, i943 UNITED STATES PATENT OFFICE VAPOR GENERATOR ErvinG. Bailey, Easton, Pa., assignor to The Bahcock & Wilcox Company,Newark, N. 1., a corporation of New Jersey Application May 13, 1939,Serial No. 273,398 Claims. (0]. 183-85) This invention relates toimprovements in vapor generators and the invention may be considered asexemplified in water tube steam boiler improvements whereby the safesteaming capacities and the water storage capacities of such boilers,for a given drum capacity, are increased.

Among the objects of the invention are the eilective separation of steamand water with a minimum of steam and water separation space; ,theelimination of priming and decrease of water content in the steamleaving the steam and water drum to a minimum; the decrease of theamount of steam in the water in the steam and water drum to a minimum sothat maximum density of water is procured; the increase of the safesteaming capacities of natural circulation steam boilers by minimizingthe amount of steam in the downtake elements; the increase in boilercirculation rates; and improvements which will enable a given water tubesteam boiler to operate. at maximum capacities under conditions ofhigher and more widely varying water levels.

To accomplish these objects the invention involves the combination ofnovel steam and water separators in a single steam and water drum and incertain definite relationships to the steam and water spaces of thedrum, and the circulators discharging steam and water into the drum. Itis to be understood, however, that the invention is not limited to allof the details of this combination.

With reference to the separators, it is an object of the invention toprovide for the optimum of steam and water separation with a minimum offlow resistance and minimum of re-entrainment of steam in the water, andwater in the steam after the initial separation.

The invention will be described with reference to the embodimentsillustrated, in the accompanying drawings, and other objects of theinvention will appear as the description proceeds.

In the drawings:

Fig. 1 is a vertical section of a steam generating installation whichincludes an embodiment of the invention,

Fig. 2 is a transverse vertical section of a steam and water drum withthe illustrative separator therein;

Fig. 3 is a plan section of a steam and water drum showing thearrangement of a number of the illustrative separators;

Fig. 4 is a vertical longitudinalscction of the, Fig. 3 drum;

Fig. 5 is a vertical section on the line- 5--5 of Fig. 6, illustratingan embodiment in which the separator casing i rifled;

Fig. 6 is a horizontal section on the line 6-6 oi'.Fig. 5;

' Fig. 7 is a vertical section (on the line 1- of Fig.8). of anembodiment in which the separator casing is formed with parallel landsor within the drum by the side grooves within the steam and water inletand is partially rifled throughout the remainder of the separatorcasing;

Fig. 8 is a horizontal section on the line ll of Fig. 7;

Fig. 9 is a vertical section (taken on the line 9-4 of Fig. 10) of aseparator embodiment in which a single groove extends from the steam andwater inlet to the outlet for separated wa ter; and

Fig. 10 is a horizontal section on the line Ill-i0 of Fig. 9.

The invention is well adapted to attain a high degree of steam and waterseparation in high pressure and high capacity steam generators such asthat indicated in Fig. 1 0! the drawings.

In this installation it is to be noted that the steam and waterseparation is accomplished within a single steam and water drum, thusillustrating the ability of the invention to provide effective steam andwater separation with a minimum of steam and water drum volume orcapacity.

In the Fig. 1 installation the steam and water mixtures are dischargedby the circulators II- at high velocity into the drum l2. Thesecirculators are shown as having their inlet ends connected to a headeri4 which-receives the and water from a plurality of risers. Some orthese risers define the walls and other boundaries of the furnace l6 andare subject to the high temperatures thereof. Other risers, such asIii-40, define the walls of gas'passes 22 and 2A and are subject to'highgas temperatures at those positions.

Steam and water is separated within the drum It, the steam proceedingthrough the tubes I}! to the superheater I 34 while the separated waterproceeds through the downcomers 30 to lower headers 32-45, the latterbeing otherwise appropriately connected into the boiler circulation asindicated. The steam and water discharged into the drum I2 through thecirc'ulators ll enters a separator inlet chamber "which is formed plateM, the upper and lower plates 44 and 46, and complementary end platesindicated at 48 and 50 in Figs. 3 and 4 of the drawings. This inletchamber extends throughout the major portion of the length of the drumand has connected thereto a plurality of rifled, steam and waterseparators ii, the air rangement of these separators being indicated inFigs. 3 and 4 of the drawings and their specific construction beingindicated in Fig. '2 and Figs.

. 5-9, inclusive, of the drawings.

In 'the illustrative separators a plurality of forces are eifectiveduring the operation of the vapor generator. Vapor and liquid mixturesenter the whirl chambers from the inlet chamber Ml with a considerablevelocity head. Their flow is Substantially tangential. to the whirlchambers and it may also be considered as substantially horizontal.These circumstances result in a swirling film of liquid flowing alongthe wall of the whirl chamber and the centrifugal for.e thus produced iseffective in separating the vapor and liquid.

As the mixture of liquid and vapor enters the whirl chamber horizontallyat a high velocity the tendency is for it to continue its motion in thesame horizontal zone, so that the film of liquid tends to flow back uponitself creating a layer of liquid of greater depth. While this tendencyis naturally modified by the force of gravity, which imposes avertically downward component, on the horizontal velocity component ofthe incom-i ing stream, ;.thus resulting in a'generally downwarddirection of the fllm of liquid on the whirl chamber wall in the form ofa spiral, the centrifugal force being greater than gravity is suchthatin acting upon the layer of liquid, the liquid displaced in thethinning down of the layer fiows both upwardly and downwardly of thewall of the: whirl chamber from the horizontal zone into .which theincoming stream is projected. It is desirable, ,however, toavoid theseconditions. As for example, .the liquid displaced upwardly of the whirlchamber wall may impactiwith the top of the whirl chamber resultinginthe splashing .of such liquid into the steam space in the center ofthe chamber, where it might be picked up by steam and carried'tothemultiple plate sepailator. or, if the distance above the horizontalz'one,"to which reference has been made, to the top of the chamber'isadequate to prevent this happening, when the centrifugal force in thisliquid is dissipated the action of gravity will be to gene the liquid toflow down-the whirl chamber trial and on contact with the high velocityincoming stream will tend to splash with the same pbs'sibility ofresultantjpickup by the steam, which is; of course, undesirable. Inorder that the forces involved might be utilized most efliciently, andthe best results as to steam-free watg'r andwater-free steam beobtained, it is necgsary that these conditions be avoided, and the m ofliquid removed from the incoming zone, and... all of it dischargeddownwardly from the bottom of the whirl'chamber just as quickly as ble.The rifled or spirally grooved interior 'all of the whirl chamberprovided by this invention performs this function, as it utilizes theentirely of the incoming stream to augment the eneet of the force orgravity, and not only defifi teiy initiate but maintain the downwardlyflow 6f the liquid'filmtowai-d the restrictedoutlets atthe lower end ofthe whirl chamber. Such restrictd outletsjare 'shownas limited to narrowannular zones defined externally by the rifled wall oftlie' whirlchamber and the base, or pan, 88;"; They maybe separated by shorthelical vanes such as thoseindicated at 58 and ill in Fig. "The latterarepreferably co-ordinated with tlie rifllng, and when secured to thewhirl chant br they serve as supports for the pan, or base, 58". Theforces involved in the flow of separated whterdownwardly through theseoutlets prevents the"establishment of liquid levels in the whirl chambercorresponding to the drum liquid levels and enables the vapor generatinginstallation to effectively operate at drum liquid levels rangingessentially from the top to the bottom of the cylindrical whirl chamber."Such as is indicated by the lines'AB and CD of Fig. 5. v

Beneath the multiple plate separator I2 for each whirl chamber the steamoutletmember 62, formed in the shape of a hollow frustum of a cone, issecured at its upper circumferential edge to the top of the whirlchamber by brazing or welding as indicated at 64; This member not 'onlyprevents the liquid swirling in an annular layer at the upper portion ofthe whirl chamber from being whipped upward so as to be caught by theplates of the separator 52 but also causes liquid falling from theseparator 52 to be deflected toward the center of each whirl chamber.

The modification of the separator indicated in Figs. 7 and 8 of thedrawings is similar to that above described in many respects, the maindifference residing in the extent of the rifllng. In the Fig. 7modification the whirl chamber is not. completely rifled, the rifllngbeing limited to asubstantiaily helical band beginning in the inlet.structure Ill and continuing through the outlet for the separated water.This leaves a plain sur-f faceportion of the interior surface of thewhirl chamber between successive groups of the rifiing elements. Such aplain surface portion is indi-. cated at I2, disposed between theelements oi the. rifling H and I6 of an upper group and elements 18 and80 of a lower group. J

The embodiment indicated in Fig. '1 of the drawings has a whirl chamberwith rifllng so,

arranged that at the time the liquid in the grooves. makes one circuitof the whirl chamber, it is below theentrance port, and there istherefore no building up of a return liquid upon the enter-; ing stream.The rifiing is thus of benefit in eifecting more definite downward fiowof the liquid swirling along the wall. I

In the embodiment indicated in Figs. 9 and 1-0 of the drawings theinterior of the casing 8! is formed with a single helical groovebeginning at the position indicated at 82 which is disposedapproximately at the junction of the inlet struc-'- ture 84 and thecasing 8L. From that point the; groove 86 extends helically to andthrough the water outlet which is formed by the base 90 and the surfaceof the casing 8! adjacent the base. i

As indicated in Fig. 2 of the drawings the whirl chamber casings aresecured to the plate 42 by sleeves H0 fixed to the plate and provided.with flanges H2 adapted to fit against compiementary flanges ill securedto the inlet strue-E tures 8 which are rigid with the casings II."

The whirl chamber casings ii are further fixed in position by supportslid-I22, the latter of which may be welded to the drum with the mem herI 2!! detachably secured thereto.

' Operating pressure, pounds Ratio This ratio is a measure of thegravity force. which separates the steam and water. Steam will beentrapped in the body of water beneath iating water are discharged intothe body of water in the drumbelow'the .water level or if the steam andthe circulating water impingexdownwardly on the water surface. It isevident that theseparating force of gravity alone decreases greatly withincreased operating pressures so that it becomes increasingly difilcultto remove any steam entrappedin the body of water as the operatingpressure increases. .Any steam so en-' trapped is carried with thecirculating water into 9 the. downcomersand, due to the smaller specificweight of the steam, the circulating head is re-' duced and hence thecirculating system balances out at a lower circulating flow. The presentin- -"vention causes all of the steam and circulating water to bereceived within separate whirl chambers within the boiler drum, and, byutilizing centrifugal force which is several hundred per centgreaterthan the force of gravity, the steam and water are completely separated.The steam is discharged vertically upward from the whirl vchambers atlow velocity and away from and above the surface of the water. Theseparated water is discharged downwardly from the whirl chambers intothe body of water within the drum.

and below theupper surface of. that body of water. In this way the bodyof water below the surface is practically free from steam, and the steamspace above the water surface is practically free from moistureregardless of operating pressure or capacity. Therefore, the water inthe downcomer supply being practically free from steam insures that themaximum circulating head is produced and the optimum circulating flow isattained, and at the same time the steam being practically free frommoisture insures the supply of clean steam to the superheater andsubsequent turbine, and the elimination of the troubles previouslyencountered in such appa- -ratus due to moisture and solids carryover inthe I factor resulting from such increased water shortage. Thesecharacteristics of the invention also permit noteworthy decreases in thecosts of original installations byinsuring satisfactory circulatingcharacteristics and good quality steam production with minimum of drumcapacity.

While the invention has been described with reference to certainparticular embodiments thereof it is not limited to all of theirdetails. On the contrary, it is to be considered as of a scopecommensurate with the scope of the subjolned claims.

What is claimed is;

1. 'In a separator for fluids of diflerent densities, means constitutinga whirl chamber, an 'inlet means so disposed as to promote the whirlingmovement of fluids within the chamber, the

inlet means having its longitudinal axis ofl'set with respect to thelongitudinal axis of the whirl chamber and transversely related thereto,the

whirl chamber being rifled internally with the with a lead which is atleast as great a the A which is .at least approximately equal to thewidth'of the inlet: axially of the whirl chamber.

2. In a fluid separator, a whirl chamber casing of circularcross-section defining a separating zone, means forming a tangentialinlet to said zone, means wherebya fluid stream is discharged throughthe inlet-at high velocity, and difierent outlets for separated, fluidsof different densities, the casing beingrifledfrom the inlet toward theoutlet for the separated fluid 0! higher density, the rifling being suchthat the lead of any element thereof is at least as great as the widthof the inlet axially-oi the whirlchamber.

3. In a fluid fseparator, a whirl chamber of circular cross section,means forming a tangential inlet to said chamber, spaced outlets forseparated fluids of diflerentdensities, means in the zone oftheperimeter of the chamber for promoting movement of thefluid at higherdensity toward the outlet fo'r that fluid, said means consisting of ahelical groove extending from the elevation of the inlet to a positionbelow the inlet width of the inlet axially oi the whirl chamber.

4. In apparatus for separating fluids of diflerent densities, a whirlchamber of circular crosssection, means forming an inlet tangentiallyarranged relative to'said chamber so that a stream of fluids enteringthe chamber at high velocity will tend to set up a'high velocitycircular movement of fluid withintthe chamber, spaced outlets forseparated fluids of diflferent densities, and means limited to theperipheralzone of the chamber and disposed adjacent the inlet forinitiatin movement oi the incominsffluid stream toward the outletfor theseparated fluid at higherdensity, said means consisting of a group ofspaced helical grooves inthe circumferential wall of said whirl chamber"extending from the elevation of the inlet to a position'below theinletandbeing such that the lead ofany groove is at least as great asthe width of the inlet axially of the whirl chamber.-

5. In a fluid separator including a shell providing a whirl chamber ofcircular cross-section and extending belowa'liquid level, inlet means,whereby the whirl chamber tangentially receives unseparated mixtures ofgas and liquid at high velocities, means forming, a gas outlet at oneend of the whirl. chamber, aliquid outlet disposed toward the oppositeends of the whirl chamber and limited to a zone adjacent the perimeterof the chamber, and helical ribs projecting into the whirl chamber fromthe shell and extending from a position adjacent the inlet to initiate ahelical motion of theliquidtoward its outlet and to prevent the secondwhirl of the liquid from the inlet from remixing impact upon the firstwhirl, the

j pitch of the said ribsbeing at least as great as

